The present invention relates to a plate exchanging apparatus in a rotary printing press for removing an old plate from a plate fixing unit of a plate cylinder and inserting a new plate.
As an apparatus of this type, one is disclosed in Japanese Patent Laid-Open No. 11-77968. The disclosed apparatus has a cassette which is swingably supported by frames and has a new plate setting unit for setting a new plate and an old storage unit for storing an old plate, and an actuator for reciprocating the cassette between two positions, a plate mounting position and a retreat position. In this arrangement, when the cassette is moved to the plate mounting position by the actuator, the distal end of the cassette opposes the plate fixing unit of the plate cylinder. When the plate cylinder rotates almost one revolution from this state, an old plate whose leading and trailing edges are released from the plate fixing unit of the plate cylinder is stored in the old plate storage unit of the cassette. After the leading edge of a new plate set on the new plate setting unit is inserted into the plate fixing unit of the plate cylinder, the plate cylinder rotates almost one revolution, and the new plate is set on the plate cylinder.
In the conventional plate exchanging apparatus, the cassette is disposed between two adjacent printing units, and the cassette has the new plate setting unit for setting a new plate and the old plate storage unit for storing an old plate. For this reason, the cassette has a large outer size to narrow the work space between the printing units and degrade workability in maintenance and inspection. Since the cassette must be reciprocated between the plate mounting position and the retreat position, a large actuator is required. This not only increases the apparatus scale but also complicates its structure.
It is an object of the present invention to provide a plate exchanging apparatus in a rotary printing press in which workability is improved.
It is another object of the present invention to provide a compact, simple plate exchanging apparatus in a rotary printing press.
In order to achieve the above objects of the present invention, there is provided a plate exchanging apparatus in a rotary printing press, which removes an old plate from a plate fixing unit of a plate cylinder and inserts a new plate, comprising a plate holder for holding the new plate, and actuator means for performing one of moving and swinging operations of the plate holder in directions to come close to and separate from the plate cylinder, wherein the actuator means selectively positions the plate holder to a first position where the new plate is held in the plate holder, a second position where the new plate held by the plate holder is retreated from an old plate removal path, and a third position where the new plate is inserted into the plate fixing unit of the plate cylinder.